/**
 * @file
 * @copyright 2020 Aleksej Komarov
 * @license MIT
 */

/**
 * Returns a function, that, as long as it continues to be invoked, will
 * not be triggered. The function will be called after it stops being
 * called for N milliseconds. If `immediate` is passed, trigger the
 * function on the leading edge, instead of the trailing.
 */
export const debounce = (fn, time, immediate = false) => {
  let timeout;
  return (...args) => {
    const later = () => {
      timeout = null;
      if (!immediate) {
        fn(...args);
      }
    };
    const callNow = immediate && !timeout;
    clearTimeout(timeout);
    timeout = setTimeout(later, time);
    if (callNow) {
      fn(...args);
    }
  };
};

/**
 * Returns a function, that, when invoked, will only be triggered at most once
 * during a given window of time.
 */
export const throttle = (fn, time) => {
  let previouslyRun, queuedToRun;
  return function invokeFn(...args) {
    const now = Date.now();
    queuedToRun = clearTimeout(queuedToRun);
    if (!previouslyRun || now - previouslyRun >= time) {
      fn.apply(null, args);
      previouslyRun = now;
    } else {
      queuedToRun = setTimeout(
        invokeFn.bind(null, ...args),
        time - (now - previouslyRun),
      );
    }
  };
};

/**
 * Suspends an asynchronous function for N milliseconds.
 *
 * @param {number} time
 */
export const sleep = (time) =>
  new Promise((resolve) => setTimeout(resolve, time));